Talk of Ed Miliband return as he shares billing with Jeremy Corbyn

Jeremy Corbyn and Ed Miliband will give a joint speech in favour of remaining in the EU today, prompting speculation that the former party leader could be about to make a comeback to frontline politics.

The two Labour MPs will join forces to warn that the environment would suffer if the UK backs Brexit in the EU referendum vote in June, during a campaign event in Doncaster.

It is the first time the former and current party leaders have appeared on stage together since Mr Miliband lost the General election, prompting a Labour leadership contest which Mr Corbyn won last year.

Labour leader, Jeremy CorbynCredit:
Mark Thomas/REX/Shutterstock

In a speech today Mr Corbyn will focus on climate change and, during a visit to a solar energy farm he will say: "Leaving the EU would mean the green spaces, clean beaches and fresh air we want to leave for our children could be at risk.

"It would risk investment in new green technologies and the jobs that accompany them, and would leave us open to the Tory agenda which has been so damaging to our environment."

Mr Miliband, who has been largely absent from frontline politics since his departure as party leader, will add: "The challenge of tackling climate change is a moral responsibility, an economic necessity and the single most important thing we can do for our children and our grandchildren and leaving the EU would rob us of the ability to overcome that challenge."

It is not clear which of the men will speak first, although they will appear on stage together.

Leaving the EU would mean the green spaces, clean beaches and fresh air we want to leave for our children could be at risk.Jeremy Corbyn

A source close to Mr Miliband denied reports that he is about to make a comeback, but confirmed the former Labour leader has offered advice informally to Mr Corbyn "when asked".

It came as a Labour source accused Andy Burnham of avoiding pro-EU speeches in a bid to win the race to become the next Mayor of Manchester.

The former leadership candidate has been criticised for not doing enough to encourage voters to remain in since he announced plans to stand for Mayor, prompting complaints among Labour colleagues that he has put personal ambition before the EU vote.

Mr Burnham is understood to be concerned that swathes of Labour voters in the north of England are leaning towards Brexit and fears that a strong pro-EU message could put some people off backing him as Mayor.

He has previously spoken of the need for Labour to be frank about the downsides of immigration, a stance his leader Mr Corbyn does not share.

A spokesman for Mr Burnham said he has been focusing on launching his campaign but is due to become more involved in the referendum debate in the coming week.

But a Labour source told The Telegraph: "He's the Shadow Home Secretary and he's nowhere to be seen - he's completely abandoning Manchester's long-term interests for his short-term personal ambition by not doing anything to keep us in the EU."